1. Technical Field
The present invention relates to an emergency call processing apparatus and method in a private switching system and, more particularly, an apparatus and method by means of which an extension subscriber of a private branch exchange can make an emergency call even if all lines are busy, as well as originate an emergency call with an extension terminal even if it is locked.
2. Description of the Related Art
In general, subscribers of a private switching system are graded in call origination, and thus sometimes they are screened from calling to specific telephone numbers. Then, dialing even to an emergency telephone number may be screened also, and thus sometimes an emergency call cannot be processed.
For example, if the calling function of an extension terminal is set in a locking mode, when a user dials a general telephone number or an emergency telephone number, an outgoing call is not transmitted to the corresponding number. Then, the user has to input a preset password, and only if the inputted password is validated, the calling function can be moved from the locking mode so as to transmit an outgoing call intended by the user.
Furthermore, if all lines connected to the private branch exchange are busy, the user of the extension terminal cannot have a call until a line becomes available.
In a private switching system adopting such technology, if an available line does not exist or a terminal is set in a locking mode, an extension subscriber cannot make a call, even in the case of an emergency.